title: Alcohol and breast cancer in women: a pooled analysis of cohort studies.
abstract: OBJECTIVE
  To assess the risk of invasive breast cancer associated with total and beverage-specific alcohol consumption and to evaluate whether dietary and nondietary factors modify the association.
  
  
  METHODS
  We included in these analyses 6 prospective studies that had at least 200 incident breast cancer cases, assessed long-term intake of food and nutrients, and used a validated diet assessment instrument. The studies were conducted in Canada, the Netherlands, Sweden, and the United States. Alcohol intake was estimated by food frequency questionnaires in each study. The studies included a total of 322647 women evaluated for up to 11 years, including 4335 participants with a diagnosis of incident invasive breast cancer.
  
  
  METHODS
  Pooled analysis of primary data using analyses consistent with each study's original design and the random-effects model for the overall pooled analyses.
  
  
  RESULTS
  For alcohol intakes less than 60 g/d (reported by >99% of participants), risk increased linearly with increasing intake; the pooled multivariate relative risk for an increment of 10 g/d of alcohol (about 0.75-1 drink) was 1.09 (95% confidence interval [CI], 1.04-1.13; P for heterogeneity among studies, .71). The multivariate-adjusted relative risk for total alcohol intakes of 30 to less than 60 g/d (about 2-5 drinks) vs nondrinkers was 1.41 (95% CI, 1.18-1.69). Limited data suggested that alcohol intakes of at least 60 g/d were not associated with further increased risk. The specific type of alcoholic beverage did not strongly influence risk estimates. The association between alcohol intake and breast cancer was not modified by other factors.
  
  
  CONCLUSIONS
  Alcohol consumption is associated with a linear increase in breast cancer incidence in women over the range of consumption reported by most women. Among women who consume alcohol regularly, reducing alcohol consumption is a potential means to reduce breast cancer risk.
authors.affiliation: Department of Nutrition, Harvard School of Public Health, Boston, Mass 02115, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Smith-Warner
authors.forename: D
authors.initials: D
authors.lastname: Spiegelman
authors.forename: S S
authors.initials: SS
authors.lastname: Yaun
authors.forename: P A
authors.initials: PA
authors.lastname: van den Brandt
authors.forename: A R
authors.initials: AR
authors.lastname: Folsom
authors.forename: R A
authors.initials: RA
authors.lastname: Goldbohm
authors.forename: S
authors.initials: S
authors.lastname: Graham
authors.forename: L
authors.initials: L
authors.lastname: Holmberg
authors.forename: G R
authors.initials: GR
authors.lastname: Howe
authors.forename: J R
authors.initials: JR
authors.lastname: Marshall
authors.forename: A B
authors.initials: AB
authors.lastname: Miller
authors.forename: J D
authors.initials: JD
authors.lastname: Potter
authors.forename: F E
authors.initials: FE
authors.lastname: Speizer
authors.forename: W C
authors.initials: WC
authors.lastname: Willett
authors.forename: A
authors.initials: A
authors.lastname: Wolk
authors.forename: D J
authors.initials: DJ
authors.lastname: Hunter
mesh_terms: D000428:Alcohol Drinking; D001943:Breast Neoplasms / Q000453:epidemiology*; D004032:Diet; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D016013:Likelihood Functions; D016014:Linear Models; D008572:Menarche; D008593:Menopause; D015999:Multivariate Analysis; D011446:Prospective Studies; D012044:Regression Analysis; D012306:Risk; D018709:Statistics, Nonparametric